Client: District of Columbia Water and Sewer Authority
Project Start: December 2016
Project Completion: March 2017
Marine Technologies, Inc. Key Personnel
Project Manager: Joe Brenner
Project Superintendent: Sean Mitchell
Owner's Representative: Tamrat Bedane
Contract No. 160030 was a one-of-a-kind visual, sonic and radar investigation based on an urgent need to inspect the Northeast Boundary Truck Sewer (NEBS). Cutting across five miles of downtown Washington DC, and spanning small (approx 120 inches) to large (approx 22 feet) diameter tunnels with different shapes and configurations, the tunnels were examined in detail by custom designed and stabilized carriages whose components had to pass through 20 inch diameter manholes.
The specially configured aluminum carriages carried eight high-definition video cameras, LED lighting, GPR (Ground Penetrating Radar) and sonic/ultrasonic testing equipment. Inspection data and verbal communications with underground personnel were transmitted real time to the Engineer's Station and Command Operations Center through a fiber optic umbilical. Safety was paramount as the inspection team encountered a variety of underground obstructions including debris, trash, tires, building materials, line, rock, sand, leaves and cracked manhole covers.
The purpose of this intense data collection effort was to provide a current baseline of existing conditions so DC water could determine where future remediation efforts should be prioritized. Like much of our outdated urban infrastructure, these poorly documented sewers, built in the late 1880's, present significant challenges. The inspection results will highlight any areas of current or future concern.